Fluorescence observation devices which supply and irradiate excitation light at a predetermined wavelength to an observing object to acquire observation images of fluorescence generated from the observing object with an imaging device have been used in, for example, various fields such as the medical field. Further, in a case of observing a temporal change in a state of an object in such fluorescence observation, a method for acquiring images in time series at a predetermined frame rate and observing the object in a moving image is used (refer to, for example, Patent Documents 1 and 2).